I was always under the impression my engine was ported in my T2, last sunday I grenaded it on the dyno, so today I started pulling it apart..
My car came with the engine that blew in it when I bought it, I have never had the Lower intake manifold off, but have had the turbo manifold off, the ports are kinda rough, but have had a little grinding work done to them it seems, but the intake ports are bone stock I see now that I have it taken apart much to my surprise..
So the question is, how much is porting worth on a turbo motor, and is it really worth it? I put down 365 rwhp on a anemic 70 psi/rotor face series 4 motor with stock intake ports... How much am I capable of getting with a decent extend port or partial bridge and a tight motor with good compression? Or should I just find a way to run more boost?...Max

 

All else being equal a well executed "street port" when combined with the right hardware to take advantage of the porting will give you up to at least 15% more power over the stock ported version.

Add to this too that the "street ported" engine will have a wider sweet spot (toque curve) and it means fun for the whole family

Down sides ?

Engine will generally make power higher up the rev range, you will loose power below 4000rpm compared to the stock port, engine will be more sensitive to back pressure in the exhaust.....Oh & initial cost, GOOD street ports cost $$$ there is allot of work doing the job right, not just grinding a few contours on the plate faces

I dont know of many guys who were unhappy with their "street port" engines after having experienced stock or mildly ported engines.

A well executed one sould provide you with strong wide power from 5000rpm to 8500rpm, which is well suited to the std Mazda box, you just gotta be prepared to rev it out Obviously depends on the turbo spec too, but in general these engines are the BEST compromise for the street with good gains in efficiency and power range.

Hope this gives you some more idea of what to consider ? It realy is free power without resorting to BOOST and the associated draw backs of using too much.....

 

Thanks Rice, I am assuming though the ported motor should spool the turbo sooner than the stock port one, and that one would want to port but minimize the overlap in order to avoid reversion, I suppose the turbine a/r and wheel trim has to be payed more attention to with a large port motor in order to stay within safe backpressure/boost ratios..Max